Major corruption bug

Bug 1:
I'm having this very strange issue where some measures for specific (or sometimes all) instruments aren't playing (as though there were no notes). Also, for some reason, changing certain settings like which voices some notes are on changes which instruments and which measures are muted. In fact, this actually happens on several other scores, even in older versions.

Bug 2:
When I tried to save one of those glitchy scores in particular, it said it was corrupted. Sometimes it gave me the option to save anyway, but it completely refused to save at other times.
I worked on this in MuseScore v4.0.1, but then when I opened it again and it said there was an update, I did the update, but on the new version, it somehow got corrupted.